Switch



D. T. SIEG EL June 27, 1939.

SWITCH Filed Aug. 51, 1936 gel,

June 27, 1939. Q T, slEGEL 2,163,919

- swITcH Filed Aug. 31, 1936 3 Sheets-Sheet 2 fla/@mri- DaL/c f gel,

June 27, 1939. D T SIEGEL 2,163,919

swr'rcn Filed Aug. 31, 19:56 s Sheets-sheet s a, ally advantageous so far as the lPatented June 27, 1939 UNITED STATES PATENT OFFICE 6 Claims.

My invention relates to circuit breakers or switches and particularly to a switch of the multiple type in which a sweep a'rm is adapted to successively contact a plurality of switch points.

' Dimculty has been experienced in the maintenance of switches of the sliding contact type through long periods of use, due to the wear incident to the abrasive action of Vpitted or oxidized faces o1' the respective contacts, with av consequent reduction in emciency of electrical contact; and my invention relates to an improved arrangement wherebythe abrasion heretofore found to take place is substantially entirely eliminated.

The desired result isv secured by providing for positive mechanical separation of the contacts in a direction perpendicular to the faces of the contacts prior to any substantial relative lateral movement of the contacts. The result is secured by the use of mechanism so arranged that the contact arm or sweep arm is rocked as a preliminary to the lateral movement of the arm between adjacent contacts. This result may be brought about in a number of different ways, three of which are illustrated herein.

'Ihe theory on which the described improvement has been found to be correct, notwithstandlng the fact that the break is comparatively slow, is that a slow break is not only unobjectionable when dealing with alternating current, but actumatter of arcing is concerned. 'Ihis is due to the fact that by a slow break, one or more alternations are certain to take place during the break, as the result of which any arc that has previously begun will be u extingmshed.

I have found also that the useful life of a switch of this character is substantially increased by the use of double contacts, Vwith mechanism for causing them to make a breakin sequence l whereby one contact, which may be termed the pilot, makes contact first when a circuit is to be closed andY breaks last when a circuit is to be broken. Thus, all the possible arcing takes place in the pilot contacts, leaving the other pair continuously clean, unpitted and without abrasive wear. Such an arrangement of the contacts is particularly useful and valuable in connection with a circuit breaker in which the switch arm u is bodily moved away from contact position coincidentally with the 1atera1 shift of the arm.

The invention will be more readily understood by reference to the accompanying drawings, in

which:

I Flg.'l is a side elevation of a multiple switch constructed in accordance with myA invention, the casing being shown in section; y

Fig. 2 is a sectional view on the line 2 2 of Fig. 1;

Fig. 3 is a sectional View on the line 3-3 of Fig. 1:

Fig. 4 is a sectional view through the center of the switch construction;

Fig. 5 is a bottom plan View of the switch casing;

Fig. 6 is a sectional view through a modified form of the switch construction; 1

Fig. '7 is a sectional view on the line 'I-l of Fig. 6;

Fig. 8 is a bottom plan view;

Fig. 9 is a fragmentary sectional view on the line 9-9 of Fig. 6;

Fig. 10 is a sectional view through a further modification, the construction shown in this and the succeeding figures being considered, in some respects, to be preferable;

Fig. 11 is a fragmentary view of the contact piece in an initial position; and,

Figs. 12, 13, and 14 are sectional views on the lines I2-I2; I3-I3; II-M of Fig. l0.

In the drawings and referring particularly to Figs. 1 to 5, I have illustrated a cup-shaped casing I0,` preferably composed of ceramic material, and a cover II. Mounted axially within the casing is a shaft I 2, adapted to be turned by a knob I3.

Surrounding the shaft Within the casing is a sleeve I4 composed of insulating material and provided with a. head having a pair of ears I5. Transverse notches I6 within -the head provide a seat for a pin I'l that extends through the shaft I2 and constitutes the means for driving the sleeve.

A driving arm I8 is seated over the sleeve by means of an aperture in the arm, the arm having lugs I9 struck out therefrom, one pair being provided at each side of the sleeve, the lugs engaging` the ears I5 on the sleeve. These constitute the means for driving the arm I8. Carried at the upper or free end of the arm I8 is a stiff coiled spring 20, mounted on a pin 2|. The free ends 22-23 oi the spring respectively lying on opposite sides of a finger 24 formed as an extension from an upward projection 25, from a. driving sleeve 26 that will later be described. A pin 21 fixed to the arm I8 separates the two ends 2 2-23 of the spring.

As best shown in Fig. 2 the driving arm I8 has shoulders 28-29 at diametrically opposite sides of the center opening in the arm and these shoulders respectively overlie the arms 30-3I of a bell crank that constitutes' the sweep arm or switch arm of the switch. The body portion 32 of the bell crank is c urved to overlie the driving sleeve 26 Yand pivot screws 33-34 seated in the driving sleeve constitute the pivot for the bell crank. The other arm 35 of the bell crank constitutes the switch arm and carries a contact piece 36. A coil spring 31 is under compression between the arm 35 and the extension 25 heretofore described. A lug 38 seated in the arm 35 is adapted `to successfully engage in notches 39 in a ring 48 that is held by means of screws 4I in the base of the casing, a notch being provided foreach of the terminals 42 of the switch.

A 'terminal 43 for current supply terminates in a contact ring 44 while a complementary ring 45 overlies the ring 44 and is mechanically connected tothe driving sleeve I4 to be rotated thereby. ,A pair 'of flexible cables 46 are soldered to the ring 45 and conduct the current directly from the ring to the contact piece 36.

The operation of the -mechanism thus far describedis as follows:

With the parts in the position shown in the drawings, it will be seen that the switch arm 35 cannot be shifted until it is withdrawn perpendicularly from the contact faces, because of the interlocking of the lug 38 with one of the notches in the rim. This is broughtabout by reason of the fact that as the shaft is turned, the drive karm .I8 through one of the shoulders 28-28- depress'es one of the projections 30-3I of thebeII-crank, thereby vcausing the switch arm to be moved away from contact engagement. The rotation of the drive Aarm I8 applies force to oneof the. spring ends 22--23 on the finger 24 that is ilxed to the drive sleeve 26 and which sleeve carries the switch arm. Thus, when the switch -arm vhas been swung backward sufficiently to disengage the lug 38 from its notch, the stored up forcein the spring end will quickly snap the switch arm and its associated parts into the next position of the switch. The freedom of movement between the drive arm I8 and the switch arm that is permitted` by the spring ends 22-23, permits the parts to resume their normal position immediately after the switch arm`is released from the notch and thus it will snap into the next successive notch without the volition of the operator.

While in the construction shown I have shown the notch 39 as provided with straight sides,

thus insuring an exact perpendicular movement of the switch arm in making and breaking contacts, yet I may prefer to somewhat incline the sides of the notches in order to secure a limited sliding movement of theY contact pieces preliminary to breaking contact.

In the construction shown in Figs. ,6 to 9, a similar result is'secured by the use of quite different mechanism. In that construction the casing 41 has a cover 48 and a shaft 49 is mounted therein in the usual manner. Extending through the shaft 49 with capacity for limited freedom of movement is a pin 50 that serves to connect a sleeve 5I.. An-'oscillating switch arm 52 is pivoted to thetsleeve 5I by means of a pin 53. A bracket 64., secured to the sleeve 5I serves as a supportffqr' acompression spring 55 that bears againstthy switch arm and tends to force it into contact engagement. A roller 56 carried by the outer end of the switch arm successively engages recesses 51 between projection 58 formed on the cover 48. One recess being provided for each contact to be made.

At its outer end the contact arm carries two contacts 59-68 the latter being connected through a leaf spring 6| to the arm. The set of the spring will be such that the contact 60 will first make engagement with the terminal piece 62. Thereafter the contact 59 will engage with the terminal piece 63 and conversely, in breaking the contact the pieces 68--62 will be last to break and will be subject to Whatever arcing takes place.`

Current is supplied through the terminal 64 to a ring 65. A rotating ring 66 driven by the shaft and insulated therefrom is connected by a flexible cable 61 to the contact piece 59-60.

It will be noted that the projections 58 have inclined sides. This with the lost motion provided between the shaft 49 and the sweep arm by the pin 50, insures that the break will b'e somewhat gradual relative to the lateral or angular motion. In other words, there will be a limited sliding motion but the contacts will be separated without sliding off the edge of the contact pieces. insures also that the contact will be made with a snap action regardless of the volition of the operator.

In the construction of Figs. 10 to 14, the base or housing 68 remains the same, the housing having a cover 69. A plurality of switch points are provided, three, only, being shown in this instance. The arrangement of the switch points is novel in that a groove 10 is provided in the base, which is preferably constructed of a dielectric material, such as porcelain, the groove providing an inclined shoulder adapted to receive one Switchpoint 1l of a pair, the other point 12 being-arranged in the plane of the base. These points are mounted on a common terminal piece The purpose for the angular arrangement of the respective points will be explained hereafter.

A shaft 14 is mounted in the casing, the lower end being received within an insulating sleeve 15, a transverse pin 16 in the shaft engaging with a slot in the sleeve to effect rotation in unison. The sleeve is provided with ears 11, engaged by lugs 18 formed on a disc 19 that constitutes a sliding contact with a terminal disc connected to a terminal 8|. A flexible cable 82 is soldered to the disc 19 at one end and at the other end to a twin piece 83. This contact piece carries contacts 84,85 arranged at an angle corresponding to that of the points 1I, 12.

The contact piece 83 is fixed on a dielectric block 86 that is pivoted at 81 to a sweep arm 88. A flat spring 89 connected to the arm bears at its outer end against the end of the block 86 and tends to swing the same as permitted by an arcuate slot 98 in the outer end of the block, the slot engaging a pin 9| carried by the arm. Thus as the contacts move toward a position to close the circuit, the contact 84 will, due to the action of the spring 88, rst make engagement with the outerswitch point 12. Continued travel of the sweep arm will serve to rock the block 86 on the pin 81 and as the contact 85 engages the point 1l a toggle action is secured. 'I'his is illustrated in Figs. 1'0 and l1 by the dotted line 81x which extends from the pivot point 94 ythrough the pivot point 81 to the center of the contact 85. In Fig. 11 it will be noted that the angle of the line lis considerably greater than in Fig. 10, the line being nearly straight in the latter figure, showing a relatively great pressure is being exerted by the toggle action.

In this construction, the same as in tho e heretofore described, the sweep arm is caused to rock and to lift the contact from engagement with a This switch point as a preliminary to angular movement of the arm. This is brought about by the following construction.

A sleeve 92 -is connected to the shaft 'M by means of a pin 93, the opening through the shaft being slotted as show'n in Fig. 14 whereby to provide for' a substantial loss of motion. The sweep arm is formed as a lever of the first order, being pivoted at 94 to the sleeve 92. A bracket 95 xed to the sleeve carries a loop spring 96 that bears against the outer end of the sweep arm and tends to force the contacts into circuit-closing position. The outer end of the sweep arm carries a roller 91 that engages with the teeth 98 of a circular rack, a number of teeth being provided to correspond to the number of switch points. 1t will be noted that the sides. of the teeth 98 'are substantially straight and in order to effect an easy disengagement of the roller therefrom, I provide a rotary cam piece 99 having less abrupt cams |09 than are provided on the teeth 98. The cam piece 991s rigidly pinned at IUI to the shaft 'Il without lost motion. Thus on the rst turning movement of the shaft, the gradual cams 00 will act on the roller 91 to force the roller out of the notch and to lift -the contacts perpendicularly out of engagement with the switch point. When the roller has been lifted to a point near the upper ends of the teeth 99, the pin 93 will then take effect to begin a turning movement of the sweep arm and the roller will ride over a tooth 98 and, on approaching the next succeeding notch, will immediately snap into the notch without the volition of the operator; this is due to the lost motion between the shaft and the arm support sleeve.

A description of operation of the respective structures has been provided in connection with a description of the structure thereof. It may be said', however, that in each structure the sweep arm is designed to be lifted perpendicularly from circuit-making contact with only a very slight drag between the contacts. This arrangement has been found to be advantageous for various reasons.

'Ihe term point or switch point as used in the claims is intended to comprehend a fixed contact of indefinite area: the term is used to distinguish, merely in terminology,from the contacts carried by a switch arm.

It should also be understood that wherever in the claims I have described the sweep arm as pivoted or connected to the operating shaft I comprehend any construction in which an insulating sleeve is interposed between the arm and shaft, as well as a construction in which shaft insulation is not and in which the arm is directly rather than indirectly connected to the shaft.

Obviously other modifications may be made than those shown and I do not wish to be limited. except as indicated in the appended claims.

-1. In combination, a base having a series of swhch points, a cover, a shaft axially arranged relative to the points, a sweep arminthe form of a lever of the first order pivoted to said shaft for oscillation thereon and rotation thereby, said arm carrying a contact, a bracket projecting from and rotatable with said shaft, a spring actingbetweensaidbracketandtheendofthearm opposite to the contact, and a series .of cams carried by the cover acting on said arm, causing the same to oscillate as a preliminary to movement of the arm away from a switch point.

2. In a switch, the combination of a base having switch points, a cover, a shaft. axially arranged relative to the points, a sweep arm rotatable by the shaft and pivoted thereto with capacity for oscillation, means providing for substantial lost motion in the connection that provides for rotation of the arm by the shaft, means carried by the cover providing a. series of notches corresponding in number to the switch points,

, said notches coacting with the arm to raise the arm out of contact prior to movement of the arm from the plane of a switch point, the said lost motion permitting said arm to engage the next succeeding notch'in advance of completion of rotation of the shaft.

3. In combination, a base having a. series of switch points, a shaft axially arranged relative to the points, a sweep arm in the form of a lever of the first order pivoted to said shaft for oscillation thereon and rotation thereby, said arm carrying a contact, a bracket projecting from and rotatable with said shaft, a spring acting between said bracket and the end of the arm opposite to the contact, and a series of cams act- .ing on said arm causing the same to rock as a preliminary to movement of the arm away from a switch point.

4. In a switch, the combination of a base having switch points, a shaft axially arranged relative to the points, a sweep arm rotatable by the shaft and pivoted thereto with capacity for oscillation, means providing for substantial lost motion in the connection that provides for rotation of the arm by the shaft, means providing a series of notches corresponding in number to the switch points said notches coacting with the arm to raise the arm out of contact prior to movement ofthe arm from the plane of a switch point, the said lost motion permitting said arm to engage the next succeeding notch in advance of completion of rotation of the shaft.

5. In combination, a base having points, a

vshaft centrally arranged relative to said points.

a' sleeve surrounding the shaft and connected thereto with capacity for substantial lost motion, a sweep arm mounted to rock on said sleeve, said arm having a contact, means remote from the points for causing the arm to rock, and to raise the arm from the points, said lost motion and said arm-raising means acting to permit the arm to drop and engage a point in advance of rotation of the shaft.

6. In combination, a base having points, a

shaft centrally arranged relative to said points.

al sleeve surrounding the shaftand connected thereto with capacity for substantial lost motion, a sweep arm mounted to rock on said sleeve, said arm having a contact, means remote from the points for causing the arm to rock, .and to raise the arni from the points, said lost motion and said arm-raising means acting to permit the arm to drop and engage a point in advance of rotation of the shaft. a terminal rotatable with the shaft and insulated therefrom, and a flexible cable connecting the terminal to the contact.

DAVID T. SEGEL. 

